1. Field of the Invention
This invention relates to an automatic, checking and collecting machine, and more particularly to a magnetic recording medium processing apparatus built in the automatic checking and collecting machine for reading magnetic bit data stored in a ticket, etc., and processing the read data.
2. Description of the Related Art
Recently, automatic checking and collecting machines have been installed in many stations to enhance the efficiency of checking tickets. These machines read magnetic bit data stored in a ticket carried by a passenger with the use of a magnetic data reading apparatus employed therein, thereby judging whether the ticket is valid or invalid, as is disclosed, for example, in Jpn. Pat Appln. KOKAI Publication No. 4-262485.
In the magnetic data reading apparatus, a reading head is opposed to a roller with a predetermined space therebetween. A magnetic recording medium such as a ticket is inserted into the space between the reading head and the roller, and magnetic bit data recorded therein is read by the magnetic head. The magnetic head in turn outputs an analog voltage which varies in accordance with whether or not magnetic bit data has been supplied from the head.
The output of the magnetic head is amplified by an amplifier and then input to a peak detecting circuit, where peak values of the bit signal are detected, and time points at which the peak values are detected are determined. The bit signal is demodulated by a data demodulating circuit at time points, at which the peak values having levels higher than a predetermined slice level have been detected by the peak detecting circuit. Thus, the contents of the magnetic bit data are analyzed. In other words, it is determined whether or not the magnetic bit data recorded in the ticket is valid. As described above, in the conventional magnetic data reading apparatus, a voltage signal supplied from the magnetic head is subjected to analog processing, to detect the time points of occurrence of its peaks and analyze the recorded magnetic bit data.
A ticket storing magnetic data is transferred at a high speed of about 2 m/s through the automatic checking and collecting machine by means of a transfer mechanism employed therein. At this time, the magnetic head cannot accurately read or write magnetic data unless the ticket is appropriately pressed against the magnetic head by a roller which is opposed to the head. Disadvantageously, the magnetic head is liable to be worn out due to friction between itself and the ticket or magnetic recording medium. If the distance between the roller and the magnetic head varies as a result of the wear, the ticket cannot be pressed against the magnetic head by a predetermined force, and hence the magnetic data may be erroneously read. To avoid such erroneous reading, a technique for adjusting the distance between the roller and the magnetic head by moving the roller toward the magnetic head is disclosed. However, this adjustment is performed only manually.